Measurement of differential cross sections of isolated-photon plus heavy-flavour jet production in pp collisions at $\sqrt{s}=8$ TeV using the ATLAS detector

Abstract

This Letter presents the measurement of differential cross sections of isolated prompt photons produced in association with a b-jet or a c-jet. These final states provide sensitivity to the heavy-flavour content of the proton and aspects related to the modelling of heavy-flavour quarks in perturbative QCD. The measurement uses proton-proton collision data at a centre-of-mass energy of 8 TeV recorded by the ATLAS detector at the LHC in 2012 corresponding to an integrated luminosity of up to 20.2 fb${}^{-1}$. The differential cross sections are measured for each jet flavour with respect to the transverse energy of the leading photon in two photon pseudorapidity regions: $|{\eta }^{\gamma }|<1.37$ and $1.56<|{\eta }^{\gamma }|<2.37$. The measurement covers photon transverse energies $25<E_{\text{T}}^{\gamma }<400$ GeV and $25<E_{\text{T}}^{\gamma }<350$ GeV respectively for the two $|{\eta }^{\gamma }|$ regions. For each jet flavour, the ratio of the cross sections in the two $|{\eta }^{\gamma }|$ regions is also measured. The measurement is corrected for detector effects and compared to leading-order and next-to-leading-order perturbative QCD calculations, based on various treatments and assumptions about the heavy-flavour content of the proton. Overall, the predictions agree well with the measurement, but some deviations are observed at high photon transverse energies. The total uncertainty in the measurement ranges between 13% and 66%, while the central $\gamma +b$ measurement exhibits the smallest uncertainty, ranging from 13% to 27%, which is comparable to the precision of the theoretical predictions.

arXiv comment38 pages in total, author list starting page 22, 3 figures, 3 tables, published in Physics Letters B, All figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2017-02/

References in corpus (54)

• The automated computation of tree-level and next-to-leading order differential cross sections, and their matching to parton shower simulations
• The anti-k_t jet clustering algorithm
• An Introduction to PYTHIA 8.2
• A Brief Introduction to PYTHIA 8.1
• FastJet user manual
• Parton distributions for the LHC
• Parton distributions for the LHC Run II
• New parton distributions for collider physics
• Event generation with SHERPA 1.1
• The ATLAS Simulation Infrastructure
• Parton distributions from high-precision collider data
• New parton distribution functions from a global analysis of quantum chromodynamics
• A parton shower algorithm based on Catani-Seymour dipole factorisation
• Comparative study of various algorithms for the merging of parton showers and matrix elements in hadronic collisions
• Pileup subtraction using jet areas
• QCD matrix elements and truncated showers
• Topological cell clustering in the ATLAS calorimeters and its performance in LHC Run 1
• Performance of pile-up mitigation techniques for jets in $pp$ collisions at $\sqrt{s}=8$ TeV using the ATLAS detector
• Jet energy measurement with the ATLAS detector in proton-proton collisions at sqrt(s) = 7 TeV
• Luminosity determination in pp collisions at $\sqrt{s}$ = 8 TeV using the ATLAS detector at the LHC
• Performance of $b$-Jet Identification in the ATLAS Experiment
• Isolated photons in perturbative QCD
• Transverse-Momentum-Ordered Showers and Interleaved Multiple Interactions
• Jet energy measurement and its systematic uncertainty in proton-proton collisions at $\sqrt{s}=7$ TeV with the ATLAS detector
• Electron and photon energy calibration with the ATLAS detector using LHC Run 1 data
• A modified cluster-hadronization model
• ATLAS Run 1 searches for direct pair production of third-generation squarks at the Large Hadron Collider
• b-Initiated processes at the LHC: a reappraisal
• Electroweak radiative corrections to b --> s gamma
• Measurement of isolated-photon pair production in pp collisions at sqrt(s) = 7 TeV with the ATLAS detector
• Measurement of the photon identification efficiencies with the ATLAS detector using LHC Run-1 data
• CT14 Intrinsic Charm Parton Distribution Functions from CTEQ-TEA Global Analysis
• Measurement of the cross section for inclusive isolated-photon production in $pp$ collisions at $\sqrt{s}=13$ TeV using the ATLAS detector
• Measurement of the Differential Cross Section for Isolated Prompt Photon Production in pp Collisions at 7 TeV
• Measurement of the inclusive isolated prompt photon cross section in pp collisions at sqrt(s) = 7 TeV with the ATLAS detector using 4.6 fb-1
• Measurement of differential cross sections for the production of a pair of isolated photons in pp collisions at sqrt(s) = 7 TeV
• Measurement of the inclusive isolated prompt photon cross section in $pp$ collisions at $\sqrt{s}=8$ TeV with the ATLAS detector
• Measurement of the production cross section of an isolated photon associated with jets in proton-proton collisions at sqrt(s) = 7 TeV with the ATLAS detector
• Soft Supersymmetry Breaking, Scalar Top-Charm Mixing and Higgs Signatures
• A practical guide to event generation for prompt photon production
• Measurement of the triple-differential cross section for photon + jets production in proton-proton collisions at sqrt(s) = 7 TeV
• In-medium covariant propagator of baryons under a strong magnetic field: effect of the intrinsic magnetic moments
• Measurements of fiducial cross-sections for $t\bar{t}$ production with one or two additional $b$-jets in $pp$ collisions at $\sqrt{s}$ = 8 TeV using the ATLAS detector
• Search for Scalar Charm Quark Pair Production in pp Collisions at $\sqrt{s}=8$ TeV with the ATLAS Detector
• Searching for intrinsic charm in the proton at the LHC
• Dynamics of isolated-photon plus jet production in pp collisions at sqrt(s)=7 TeV with the ATLAS detector
• Measurement of the differential photon+ c-jet cross section and the ratio of differential photon+ c and photon+ b cross sections in proton-antiproton collisions at sqrt(s) = 1.96 TeV
• Measurement of the photon$+b$-jet production differential cross section in $p\bar{p}$ collisions at $\sqrt{s}=1.96~\TeV$
• Measurements of integrated and differential cross sections for isolated photon pair production in $pp$ collisions at $\sqrt{s}=8$ TeV with the ATLAS detector
• High-$E_{\mathrm{T}}$ isolated-photon plus jets production in $pp$ collisions at $\sqrt{s}=$ 8 TeV with the ATLAS detector
• Status and Prospects of Top-Quark Physics
• Rapidity distributions in exclusive Z + jet and photon + jet events in pp collisions at sqrt(s) = 7 TeV
• Measurement of the cross section for direct-photon production in association with a heavy quark in $p\bar{p}$ collisions at $\sqrt{s}$ = 1.96 TeV
• Comparison of the Z/gamma* + jets to gamma + jets cross sections in pp collisions at sqrt(s) = 8 TeV

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